Wireless telegraph receiving system



June 16, 1931. J. BROWN I WIRELESS TELEGRAPH RECEIVING SYSTEM 2 Sheets-Sheet l Filed June 19 TORNEY INVENTOR JOHN BROWN June 16, 1931., J, BROWN WIRELESS TELEGRAPH RECEIVING SYSTEM 2 Sheets-Sheet 2 Filed June 19, 1925 N R W H O N T B R N E l o 0 Fig. 5

Patented June 16, 1931 JOHN BROWN, OF GI-IELMSFORD, ENGLAND, ASSIGNOR T RADIO CORPORATION OF AMERICA, A CORPORATION OF DELAWARE WIRELESS TELEGRAPII RECEIVING SYSTEM Application filed June 19, 1925, Serial No.

This invention is an improvement in or modification of the invention described in the specification of the British Patent No. 199,471, which describes and claims a receiving system having two radiogoniometers connected to a common pair of frame aerials, in such a manner that two stations which are in different directions with respect to the receiving station may be received independently.

In one arrangement described and claimed in that specification, there were two radiogoniometers for each receiver, the field coils of one being connected to the receiving aerials, while the field coils of the other were connected to artificial aerials possessing the same characteristics as the receiving aerials.

An object of this invention is to provide an improved aerial system of the above type which is simple in structure, utilizing half the number of radiogoniometers required in aerials of this type heretofore known and withal simple and efficient in operation.

Another object of this invention is to provide means whereby reaction between radieogoniometer field coils and frame aerials associated therewith due to rotation of the search coils is prevented.

According to the present invention a single radiogoniomete'r with divided field coils is used for each receiver, half of each field coil being connected to the receiving aerials, while the otherhalf of each field coil is connected to artificial aerials having the same characteristics as the receiving aerials. The connections of the single radiogoniometer to theaerial and to the receiver are similar to those shown in the specification of British patent No.199471 for the double radiogoniometers, i. e. the artificial aerials can be connected in parallel when only two receivers are used, but are connected in series when more than two receivers are required to operate on the one aerial. I

The invention is particularly described in connection with the accompanying drawings, in which Figure 1 shows diagrammatically a general arrangement of a receiving system in accordance with one embodiment of the invention, Figure 2 shows an end view of one 38,138, and in Great Britain Ju1y 1, 1924.

arrangement of the radiogoniometer field coils, Figure 3 shows diagrammatically part of a general arrangement of a receiving system in accordance with another embodiment of the invention, Figure 4 shows another arrangement of one set of the radiogoniometer field coils, and Figure 5 shows yet another arrangement of one set of the radiogoniometer field coils,

Referring more particularly to Figure 1, A and D are frame aerials and artificial aerials respectively. X and Y are radiogoniometers, whose field coils are each divided into halves F and F wound to have inductances suitable to the receiver and aerial systems with which they are to be used. The half field coils F are connected with the frame aerials A and the half field coils F with the artificial aerials D which are each electrically equivalent to the frame aerials with which each is associated through the half field windings. In this case as in British specification No. 199,471 referred to above any coupling between the field coils of the several radiogo- .niometers is anti-coupled via the artificial aerials, thus reducing to zero reactive effects in either receiver circuit caused by rotation of the field coil associated with the other receiver. According to applicants novel invention this anti-coupling is obtained by properly winding and arranging the several half windings of each of the radiogoniometers so that any couplings between the search coils S0 S0 through the aerials A are anticoupled through the artificial aerials D. The centre coil of one active field coil is earthed in the usual way as at K, in order to maintain the static balance of the aerial system. S01 and SC are search coils provided as in the usual method with the radiogoniometers 'X and Y.

Figure 2 shows an end view of one arrangement of the radiogoniometer field coils, the

full lines representing the field coils cooperatin g with the frame aerials, the dotted lines representing those co-operating with the artificial aerials. It will be apparent that with this arrangement there will be mutual inductance at the points marked A, B, C, D,between the half coils adjacent at those points. In

general such mutua-l inductances are small and have not been found to be of any appreciable detriment, but if required they may be balanced out in any well known way. It is possible, however, that when adjacent receivers are operated on the same wave length, spurious residual effects may occur, and to avoid these it is prefered to wind the field coils as shown in Figure 4-, and to employ the radiogoniometers so formed in the arrangement shown in i igure 3.

In this method of winding (Figure 4) the field coils for the frame aerials and for the artificial aerials are wound side by side, the windings being distributed across the wind ing form in the manner usual for radiogoniomet-ers, so that there is no mutual inductance between coils at right angles.

In Figure 4 the full lines represent the field coils cooperating with the frame aerials, and the dotted lines those co-operating with the artificial aerials, one set of field coils only being shown for the sake of clearness.

With such a method of winding, mutual inductance between the frame and artificial systems completely wipes out the coupling to the search coil, since the magnetic fields mutually cancel, and it is therefore necessary to insert a mutual inductance tending to produce results.

Figure 3 illustrates a method of accomplishing this, B representing the required mutual inductance between one of the frame aerials and one of the artificial aerials, the others not being shown for simplicity. An important advantage of this method lies in the fact that by altering the value of the balancing neutral inductance B between Zero and the value of the mutual inductance between the frame field coils and the search coil, any desired degree of coupling up to this value may be obtained, and the same radiogoniometer may therefore be used over a large range of wave lengths and different sized aerials. The coil. of these balancing mutual inductances may be of quite small dimensions. It is apparent that with this arrangement it is necessary to mount the balancing mutual inductances so that there is no coupling between that for one of the two directional aerial systems (north-south) and that for the other (eastwest) forming the frame aerial system.

Figure 5 shows another method of winding the field coils of the radiogoniometers, so as to obtain balance, only one set of field coils is shown (as in Figure 4), the full lines representing those for the frame aerials and the dotted lines those for the artificial. It will be seen that in this arrangement parts of each field coil are balanced with respect to the centre of the winding form. This method is in some cases unsatisfactory, however, for the reason that since the two systems lie intwo different parts of the magnetic field of the radiogoniometer, there will be two different coupling errors which may be of sufficient importance to render necessary the design of special radiogonimeters.

Again, it is possible to construct the field coils by winding two layers, one layer representing the frame aerial field coils, and the other the artificial aerial field coils.

Having now particularly described and ascertained the nature of said invention and in what manner the same is to be performed, I declare that what I claim is 1. In a system of the character described a plurality of radiogoniometers connected to a common directional receiving antenna, a pair of field coils in each radiogoniometer connected to the antenna, a second pair of field coils in each radiogoniometer connected to an artificial aerial, a single search coil in each radiogoniometer, said field coils and search coils arranged so that flux from the pairs of field coils in each radiogoniometer links with its corresponding search coil, and so that the reactance of one. search coil upon another is neutralize-d.

2. In a directional aerial system, a plurality of frame aerials, a plurality of artificial aerials, a plurality of radiogoniometers each having a pair of separated field windings connected with one of said frame aerials, and a second pair of field windings connected with one of said artificial aerials, and a search coil coupled to each of said radiogoniometers.

3. In a directional aerial system, a plurality of frame aerials, a plurality of artificial aerials, a plurality of radiogoniometers each having a pair of separated field windings connected with one of said frame aerials,

and a second pair of field windings connected I with one of said artificial aerials, the field coils of each radiogoniometer being wound in such a manner as to substantially prevent mutual inductance, and a search coil coupled to each of said radiogoniometers.

4. In a directional aerial system, a. plurality of frame aerials, a plurality of artificial aerials, a plurality of radio goniometers each having a pair of separated field windings connected with one of said frame aerials, a second pair of field windings connected with one of said. artificial aerials, said field coils of each radiogoniometer being distributed across the winding form to prevent mutual inductance between similar windings, and a search coil coupled to each of said radiogoniometers.

5. In a directional aerial system, aplurality of frame aerials a. plurality of artificial aerials, a plurality of radiogoniometers each radiogoniometer having a pair of separated field win-dings in series with one of said aerials, an inductance between portions of said first named field windings, a second pair of field windings in each of said radiogonioineters connected with one of said artificial aerials, an inductance in series with said second named pair of field windings coupled to said first named inductance, and a search coil coupled to each of said radiogoniometers.

6. In a directional aerial system, a plurality of frame aerials, a plurality of artificial aerials, a plurality of radiogoniometers each radiogoniometer having a pair of separated field windings in series with one of said aerials, an inductance between portions of said first named field windings, a second pair of field windings connected with said radiogoniometer and with one of said artificial aerials, an inductance in series with said second named pair of field windings variably coupled to said first named inductance, a connection between the mid-point of one of said inductances and the earth, and a search coil coupled to each of said radiogoniometers.

7. In a directional aerial system a plurality of frame aerials, a plurality of artificial aerials, a plurality of radio goniometers each having a pair of separated field windings, means for connecting one of said windings with one of said frame aerials and the other of said windings with one of said artificial 'f ones of said field coils to obtain a static balance, a search coil coupled to each of said radio goniometers and means for connecting said search coil to a receiver.

8. In a directional aerial system a plurality of frame aerials, a plurality of artificial aerials, a plurality of radi-goniometers, each having a pair of separated field windings one of each connected with one of said frame aerials, a second pair of field windings one of each connected with one of said artificial aerials, said field windings of each radiogoniometer being distributed across the winding form similar windings being at right angles to prevent mutual inductance therebetween, and a search coil coupled to each of said radio-goniometers.

9. In a' directional aerial system, a plurality of stationary frame aerials, a plurality of radio-goniometers, a plurality of artificial aerials, a plurality of pairs of cooperating field windings in each of said goniometers, the

pairs of field windings in each goniometer eing at right angles to one another and one winding of each of said pairs being associated with an artificial aerial and another winding of each of said pairs being associated with one of said frames, and a search coil coupled to the windings in each of said radiogoniometers.

10. In a radio-goniometer to be used with an aerial system comprising a plurality of frame aerials, a plurality of pairs of field windings in said goniometer, each pair of field windings comprising a pair of conductively separated and inductively coupled windings, and a search coil mounted for rotation in the field of said windings.

11. An arrangement as claimed in claim in which similar field windings are mounted at right angles with respect to each other.

- JOHN BROWN. 

